127 research outputs found
Data and Models in "Final Moments II: Observational Properties and Physical Modeling of CSM-Interacting Type II Supernovae"
No full text<p>Data and models used in publication "Final Moments II: Observational Properties and Physical Modeling of CSM-Interacting Type II Supernovae" by Jacobson-Galan, W.V., et al, ApJ, 2024a. </p>
<p>ArXiv link: <a href="https://arxiv.org/abs/2403.02382">https://arxiv.org/abs/2403.02382</a></p>
<p>Data/models also aceesible on Github: <a href="https://github.com/wynnjacobson-galan/Flash_Spectra_Sample">https://github.com/wynnjacobson-galan/Flash_Spectra_Sample</a></p>
<p>Citation: <a href="https://ui.adsabs.harvard.edu/abs/2024arXiv240302382J/exportcitation">https://ui.adsabs.harvard.edu/abs/2024arXiv240302382J/exportcitation</a></p>
<p>File structure: "Data" folder contains Gold, Silver and Comparison sample data, both spectroscopic and photometric, as well as bolometric light curves and PDFs of plots and model matches. "Models" folder contains model spectra/photometry from CMFGEN/HERACLES and SNEC simulations. </p>
A modeling perspective on the diversity of red-supergiant stars exploding within circumstellar material
No full textInternational audienceWith the ever faster cadence of untargeted surveys of the sky, the supernova (SN) community will capture in the coming years a growing number of shock breakouts in red-supergiant (RSG) stars. Expecting a high frequency of breakouts within circumstellar material (CSM), we have produced an extended, regular and cubic grid of models covering from low- to high-energy explosions, compact to extended CSM, moderate- to high-density CSM. Here, we document the main results from the radiation-hydrodynamics and nonlocal thermodynamic equilibrium radiative-transfer calculations over the first 15d of evolution, including the bolometric and multi-band light curves and the salient features from spectra. As before, CSM interaction is found to boost the UV brightness and shorten the optical rise time if compact. Higher ionization (e.g., as seen with OVI3820A) is obtained for more compact CSM, and is maximum for explosions in a vacuum. CSM interaction also diversifies the spectral evolution as seen in line profile morphology, with electron-scattering broadening dominating during the IIn phase. In the absence of CSM, Doppler broadening dominates immediately after shock breakout and leads to strongly blueshifted emission in lines such as HeII4686A or CIV5805A. This treasury of models will be used to analyze as well as predict future observations of RSG shock breakouts in CSM
There's nae Room for twa: Scotch ballad
No full textIt was in simmer time o' yearTo Mrs. W.V. Pettit."by he Author of Norah & Dermot..." -- Cover
Comparison of Effectiveness of Removing Nitrate in Two Different Wastewater Treatment Processes Used at Crepe Rubber Factories In Sri Lanka
No full textWar in the Great Northwest
No full text"The author, W.V. Rinehart, was a well known pioneer of the Pacific northwest… He was a distinguished member of the Military Order of the Loyal Legion. This paper was read by him before the Tacoma, 1914, meeting of that organization.
ÁLVAREZ CONDE, Enrique;Figueruelo BURRIEZA, Ángela ; NUÑO GOMEZ , Laura (Dir.) ; CANCIO ÁLVAREZ, Ma. Dolores (Coord.), Estudios Interdisciplinares sobre Igualdad, Madrid, Iustel, 2011. 798 pp.
No full textVillalobos, WV (reprint author), Univ Talca, Talca, Chile
Wind speed feedforward control for a wind turbine using LIDAR
No full textWind energy has relatively minor environmental impact compared to traditional energy sources. It doesn’t consume fuel or emits air pollution, while the land used for a wind farm can still be used mostly for other purposes such as agriculture. Some people state that wind turbines consume subsidies as a fuel, since they aren’t profitable without it. They use a blurred view on the real costs of energy, since they do not consider the costs associated with the pollution of the fossil energy sources. Despite this, wind energy has to deal with the public opinion that wind energy is expensive and should look for opportunities to reduce the prices. This can be done by reducing cost, increasing the yield or by extending the lifetime of the turbine. The latter can be achieved by reducing the loads on the structure. The rotor speed of a wind turbine is the result of the balance between the aerodynamic and the generator torque. Most of the utility scale variable speed wind turbines currently use a rotor speed feedback controller to control this torque balance. They can adjust the captured aerodynamic torque by changing the angle of the blades relative to the wind. But, the effect of changes in the wind on the rotor speed is delayed due to the inertia of the rotor. Meanwhile the construction suffers from the variations in the loads. For this reason it would be advantageous to measure the wind speed and use it for control, in order to anticipate on changes in the wind earlier and reduce the loads on the structure resulting in an extended lifetime of the turbine. The wind speed is currently measured on most turbines, however this measurement is useless for control, since it is contaminated by the wake of the rotor of the turbine. LIDAR is a measurement technique, which is able to measure the upcoming wind speed in front of the turbine using a laser. This measurement technique is relatively new to the wind energy market and an optimal configuration for the measurement is yet to be defined. So are the possibilities for using these measurements in a control system. A realistic simulation environment is required to investigate this and come to a reliable conclusion. This environment is created using a coupling between the simulation software packages Bladed and Simulink. It provides the possibility to co-simulate the nonlinear model of the turbine in Bladed together with a new controller in Simulink. Bladed provides simulated ‘line-of-sight’(LOS) LIDAR wind speed measurements from the wind field used. Multiple LOS measurements are combined to determine a mean wind speed representative for the whole rotor plane. How well the reality is approximated depends on the number of LOS measurements considered, the measurement distance(s) and number of measurement points per distance. The performance of the wind turbine using various LIDAR configurations is compared. The knowledge about the upcoming wind is used in the controller by adding a wind speed feedforward loop to the existing rotor speed feedback controller. The performance of the wind turbine using two different feedforward controllers is investigated. Controller A is based on the optimal pitch action for the wind at the turbine. While controller B is based on the difference between the actual pitch angle and the optimal pitch angle related to the wind speed measured at some distance. The feedback controller parameters are relaxed while using these feedforward controllers in order to achieve load reductions without deteriorating the rotor speed control. Feedforward controller B performs best for the load reduction, with reduced pitch rate demands, while having still sufficient disturbance rejection in the rotor speed control. This is because it takes more time to compensate for the virtual pitch error, resulting in lower pitch rate demands and thrust related loads. Filtering the measured wind speed adequately is a crucial step in the load reduction for controller A while controller B has this property by design. The filter effect of controller B changes with the wind speed as higher wind speeds provide less time to compensate for the upcoming changes in the wind. The optimal configuration of the LIDAR for the XD115 appears to be the pulsed system with four points on the azimuth at each of the three measurement distances. This configuration provides early knowledge about upcoming changes in the wind speed, while having sufficient coverage of the complete rotor plane.Delft Center for Systems and ControlMechanical, Maritime and Materials Engineerin
Fredholm alternatives for nonlinear A-proper mappings with applications to nonlinear elliptic boundary value problems
No full textAbstractLet X and Y be real Banach spaces with a projectionally complete scheme Γ = {Xn, Pn; Yn, Qn} and let T: X → Y be an asymptotically linear mapping which is A-proper with respect to Γ and whose asymptotic derivative T∞ ϵ L(X, Y) is also A-proper with respect to Γ. Necessary and sufficient conditions are given in order that the equation T(x) = ƒ be solvable for a given ƒ in Y. Under certain additional conditions it is shown that solutions can be constructed as strong limits of finite dimensional Galerkin type approximates xn ϵ Xn. Theorems 1 and 2 include as special cases the recent results of Kachurovskii, Hess, Nečas, and the author. The abstract results for A-proper mappings are then applied to the (constructive) solvability of boundary value problems for quasilinear elliptic equations of order 2m with asymptotically linear terms of order 2m − 1
Controlling smart metering - The design of a risk control framework for the transition phase of the smart meter roll out project
No full textTechnology, Policy and Managemen
The Effect of Letrozole on Bone Age Progression, Predicted Adult Height, and Adrenal Gland Function
No full text- …
